For balls 22mm and 608 bearing in center.
The spinner became to be very heavy, 150grams
Be careful when playing with it.
To insert balls in it, warm up the spinner a little with a hair dryer, after that the balls go easily to their seats and stay there tightly (of course if you printed it from PLA).
In general, the 22mm balls are very well held and in any usually spinner instead the 608 bearing, but that they do not exactly drop out and fall on my foot I make grooves under the balls.